ip addressing whether using private ip from 10 or 192 subnet ain't gonna increase speed.
things to increase speed are:
1. duplex settings of both PC and PS3 - try not to run auto negotiation and manually set the speed to 100 FULL or 1000 full etc.. this is full duplex (effectively meaning 100 up 100down...theoretically giving 200 pipe but as in reality with tcp/ip overheads, windowing etc you will get is approx 11MB/s (megabytes/sec remember speeds listed on PC/PS3 are megabits/sec).
If you got direct connection to PC using crossover cable then manually set to full duplex.
if you got a switch/router that both PC/PS3 connect to; set connection manually i.e FULL or auto (duplex) on all 3 devices (smart switches/routers allow for per port setting AUTO/FULL/HALF) keep it the same. very important NOT to buy elcheapo stuff esp when dealing with GIG Ethernet...you want the switch decent spec not those $10 cheapies , PC NIC to be able to push data without causing high CPU utilization. Cables are are also very important and how they are terminated --->read Quality cat 5e /cat 6.
if you got a HUB in between connecting the ps3 /pc then definitely set all PC/PS3 to half duplex to cater for collision detection.
never mismatch duplex settings and i personally don't like the Ethernet auto negotiation as most times they don't yield optimum performance and set one end to half duplex (switch to PS3) and (PC to switch) full.. this will give a perfomance hit. If you know your cables/switch are all A OK.. manually set em.
2. if you got on board av/firewall disable em when transferring data to PS3 (this also yeilds gains).
and for the love of god don't do WiFi transfers...
Also pays to own a fast PC with good disk i/o
3. if you got SPI firewall etc.. running on lan side of things and you know your lan is secure disable it... you don't want packet inspection happening for something such as this...QoS can also be helpful (if your lan is saturated).
match speeds/duplex and have fun.